The rarity of Pseudomyxoma peritonei, its complex biology and the remaining inconsistencies in terminology all contribute to rendering therapeutic recommendations a difficult task. In principle, a multimodal concept combining cytoreductive surgery with peri- and postoperative intraperitoneal chemotherapy constitutes the preferable treatment. Initially, surgical peritonectomy aims to achieve the complete removal of tumor cells at the macroscopic level. Subsequently in the early postoperative phase when the absence of adhesions allows for a homogeneous intraabdominal spread of cytotoxic drugs, intraperitoneal application of 5-fluorouracil and mitomycin C represents the most solidly established treatment. Therapeutic failures are often due to insufficiently radical cytoreductive surgery or a lack of homogeneous distribution of cytotoxic drugs in the abdomen. In view of the rarity of their condition, patients with Pseudomyxoma peritonei should be treated at or in conjunction with specialized centers. Only such a "center-oriented" approach will secure the standardization of treatment and help to clarify unsettled therapeutic questions. The development of improved therapeutic concepts will depend on concise histopathological classification. Already at present therapeutic decisions should not only be be based on the clinical aspect of a "mucinous abdomen" but should be guided by the pathological differentiation between disseminated peritoneal adenomucinosis (DPAM), with a relatively good prognosis, and the more aggressive peritoneal mucinous carcinomatosis (PMCA).